Search Results (316)

Pump-as-Turbine (PaT) systems represent a cost-effective solution for hydraulic energy recovery in existing water networks and industrial processes. However, the prediction of their performance in turbine mode remains challenging, especially under off-design conditions where unsteady flow structures and internal losses strongly affect the machine efficiency. In this work, transient CFD simulations of a real industrial centrifugal pump operating as a turbine are performed using OpenFOAM and ANSYS CFX and compared with available experimental data. The investigated operating range extends from $0.7Q_{\mathrm{BEP}}$ to $1.3Q_{\mathrm{BEP}}$. A mesh independence analysis is first carried out using the Grid Convergence Index method, leading to the selection of a mid-size computational mesh as a compromise between accuracy and computational cost. The transient OpenFOAM results show close agreement with the ANSYS CFX predictions over the complete operating range. Both numerical frameworks reproduce the experimental hydraulic-efficiency trend and the location of the BEP, while systematic deviations in hydraulic head and mechanical power are mainly attributed to the geometrical and physical simplifications adopted in the common computational model. The local pressure coefficient monitored at the tongue region shows that both the mean pressure level and the fluctuation amplitude increase with flow rate, indicating stronger transient behavior under high-flow conditions. Beyond the global performance comparison, the flow field is analyzed using $Q_{crit}$ iso-surfaces, mean circumferential velocity, the swirl-intensity parameter $S_{\mathrm{int}}$, relative velocity fields at the PaT operational leading edge, and volute head-loss evaluation. The results show that part-load operation is characterized by strong outlet vortical structures and high residual swirl intensity, while the BEP region corresponds to reduced outlet rotational content. Under overload conditions, the outlet swirl remains limited, but the volute head loss increases significantly, becoming a dominant contributor to the efficiency drop. The study demonstrates that PaT performance cannot be interpreted from outlet swirl alone, but results from the combined effect of residual rotational structures, tongue-region unsteadiness, impeller incidence conditions, and volute dissipation. Full article

Electrified steam methane reforming (eSMR) is emerging as a promising technology for the decarbonization of the chemical industry and low-carbon hydrogen production by coupling renewable electricity with renewable gaseous feedstocks such as biomethane. In this work, structured Ni-based catalysts washcoated on highly thermally conductive SiC open-cell foams (OCFs) were developed and evaluated for biomethane steam-reforming operating conditions. Two catalyst formulations, 30 wt.% Al₂O₃_30 wt.% CeO₂_20 wt.%Ni and SiC_30 wt.% Al₂O₃_30 wt.%Ce_0.25Zr0.75 O₂_20 wt.%Ni, were tested in a laboratory-scale indirectly electrically heated reformer. The high thermal conductivity of the SiC-structured support ensured efficient heat transfer throughout the reactor, limiting radial temperature gradients to below 10 °C. Both catalyst formulations exhibited excellent catalytic performance; however, the Ce_0.25Zr0.75O₂-promoted catalyst achieved the best results, maintaining equilibrium methane conversion at a gas hourly space velocity above 7000 h⁻¹ while reaching a specific electrical energy consumption of 2.06 kWh/Nm³ of produced H₂ projected for industrial-scale efficiency. Notably, these performances were obtained with a catalyst loading approximately 20–50% lower than that of conventional commercial alumina pellet catalysts. XRD characterization did not reveal the formation of crystalline graphitic carbon after catalytic operation. Furthermore, the structural evolution of the Ce–Zr–O highlights the active role of the mixed oxide in promoting redox processes and maintaining catalytic activity under reaction conditions. Overall, these results demonstrate that the combination of highly conductive SiC-structured supports and Ce–Zr-promoted Ni catalysts significantly enhances both the thermal and catalytic efficiency of eSMR. The proposed catalyst provides a promising route toward compact, energy-efficient, and decentralized hydrogen production from biomethane, supporting the electrification and decarbonization of future hydrogen generation technologies. Full article

A novel composite phase change material (CPCM) was developed by combining carbonized melamine foam (CMF) with chemically bonded silicon carbide–carbon nanotubes (SiC–CNTs) hybrid network. CMF is prepared through the carbonization process, and a graphitized layer is formed on the surface, and a continuous carbon network structure is formed inside. SiC–CNTs form a continuous thermal conduction path through covalent bonding. The experimental results show that the thermal conductivity of the CPCM is increased to 1.2117 W/m·K, which is 4.3 times higher than that of pure paraffin (0.2813 W/m·K), and the latent heat retention rate is 79%. The CPCM exhibits excellent cycle stability, and the ΔH attenuation is less than 5% after 100 cycles. The composite material has excellent thermal properties and structural stability, providing a new and efficient energy storage material choice for the field of thermal management. Full article

The ancestral method of sparkling wine production requires no sugar addition and is based on a single alcoholic fermentation that finishes in the bottle. It has recently gained popularity among both natural and conventional producers due to its capacity to expand sparkling wine portfolios and its advantages for sparkling wine production in warm regions such as the Mediterranean basin. However, some technological and other key aspects of the process remain poorly defined. This study investigates how must settling (using pectolytic enzymes) and pre-bottling filtration influence the physicochemical composition, colloidal structure, foaming properties, volatile profile, and sensory attributes of ancestral sparkling wines. Macabeo grapes (2023 vintage) were vinified under four treatment combinations of these two operations, and the wines were analysed after eighteen months of lees ageing. Significant differences were observed in total polyphenol index, titratable acidity, macromolecular composition, and colloidal particle concentration. Non-settled wines exhibited higher colloidal loads and lower foamability, whereas settling and filtration improved foam height and stability. Volatile (GC-Headspace) analysis showed that settled wines contained higher concentrations of fruity and floral esters, while non-settled and non-filtered wines had greater levels of volatile phenols and volatile acids associated with unpleasant aromas. Sensory assessment confirmed perceptible differences between treatments, particularly in phenolic, fruity/floral, and Maillard reaction aromaticity. These findings provide insights into the impact of two critical oenological practices on wine stability and aroma and provide technologically relevant guidance for optimizing quality in this emerging sparkling-wine category. Full article

The prolonged outdoor storage of coal gangue leads to significant environmental issues, while the contamination of water by antibiotics poses a worldwide health concern. Conventional adsorbents are often hindered by their expense and fragility. Current studies on ceramsite derived from coal gangue have not successfully combined the repurposing of solid waste with the management of water pollution. This research utilized coal gangue and waste electric porcelain as primary materials, incorporating 2 wt.% calcium carbonate as a foaming agent, and produced ceramsite through a gradient-heating sintering process. The investigation thoroughly examined how sintering temperature and particle size distribution influenced the material’s performance. Findings indicated that mullite-based ceramsite, sintered at 1400 °C for 15 min, achieved an apparent porosity of 35.68% and a compressive strength of 10.03 MPa. A particle size distribution following a normal model resulted in a 7.9% removal efficiency of 20.00 mg/L tetracycline hydrochloride in just 30 min, with a minimal post-adsorption strength decrease of 3.7%. This study offers a theoretical framework and practical guidance for the effective utilization of coal gangue and the economical treatment of antibiotic-laden wastewater. Full article

The sustainable isolation of nonamphiphilic phytochemicals remains a formidable challenge in biochemical engineering. In this study, a highly efficient and solvent free foam fractionation process was developed for recovering rosmarinic acid from botanical extracts. By systematically screening diverse biological surfactants, whey soy protein emerged as an exceptionally robust dual functional frother and nanoscale collector. Response surface methodology optimized the operational parameters to 850 mg/L protein concentration, pH 2.5, and a gas flow rate of 470 mL/min, yielding an outstanding target recovery of 93.08 percent alongside an enrichment ratio of 1.81. This macroscopic separation superiority was comprehensively elucidated at the molecular level through multiple spectroscopic techniques and computational modeling. Results confirmed a spontaneous static quenching complexation driven by synergistic noncovalent forces, predominantly hydrogen bonding, van der Waals interactions, π-stacking, and salt bridges. These interactions induced targeted conformational unfolding within the protein backbone, exposing hydrophobic domains that drastically elevated the thermodynamic affinity for the ascending gas–liquid interface. Furthermore, the concentrated product exhibited an antioxidant capacity enhancement exceeding 3.6 times compared to the crude extract, a result attributed to selective enrichment combined with the structural shielding effect provided by the protein macromolecule. Ultimately, this work provides critical mechanistic insights and establishes a scalable technological framework for the green purification of highly valuable botanical compounds. Full article

The current trend in both academic research and industrial applications is to expand the use of additive manufacturing processes across an increasing number of functional domains. This has led to substantial efforts aimed at improving the overall performance of additively manufactured components, particularly those produced by Material Extrusion (MEX). One of the main limitations of MEX-fabricated parts is the presence of air voids formed between deposited lines and layers, which reduce mechanical strength and structural uniformity. In this context, the present study investigates the influence of inter-layer ironing process parameters, an approach intended to modify near-surface morphology and improve the surface quality and dimensional accuracy of two commonly used materials, namely lightweight polylactic acid (PLA-LW) and standard. The experimental setup involved varying the ironing direction, nozzle diameter, and ironing spacing, while keeping all other manufacturing parameters constant. A complete 4 × 3 × 3 factorial experimental design was employed, considering three process parameters: ironing direction at four levels, nozzle diameter at three levels, and ironing spacing at three levels, resulting in 36 parameter combinations applied to each material separately. Performance evaluation included surface roughness (S_a), Shore D hardness, waviness (W_a), microscopic morphology analysis, and qualitative ultrasonic inspection used to observe internal void-related features, whereas the quantitative analysis focused on Sa, Wa, and hardness variations. The results were compared with those obtained for specimens produced using final-layer-only ironing and no ironing. Inter-layer ironing generally improved surface quality compared with non-ironed specimens, reducing Sa by up to 85.22% and increasing Shore D hardness by up to 10.40% for individual PLA-LW specimens manufactured using the 0.4 mm nozzle. The waviness response was strongly material-dependent; increasing the ironing spacing from 0.1 to 0.3 mm reduced Wa by 47.71% for PLA-LW and 13.39% for standard PLA, while the same spacing increase reduced Sa by 25.61% for PLA-LW but increased Sa by 10.87% for standard PLA. While PLA-LW specimens exhibited localized surface defects possibly associated with the compaction or collapse of near-surface voids, standard PLA specimens showed more pronounced waviness and material accumulation, highlighting the different responses of compact and foamed polymer structures to repeated thermo-mechanical ironing actions. Full article

The foam injection molding process for expanded polypropylene (EPP) offers advantages in energy efficiency, material savings, and mechanical performance, making it suitable for automotive and packaging applications. However, its nonlinear and multivariable nature makes accurate prediction and process optimization difficult using traditional methods. This study presents an AutoML-based surrogate modelling framework for predicting and optimizing two key process outcomes: cycle time and warpage. Experimental data were obtained from 81 production trials conducted on a Teubert injection molding machine using five process parameters. The PyCaret library was used to automate model selection, hyperparameter tuning, and performance evaluation, and 18 regression algorithms were compared. The results showed that tree-based ensemble models clearly outperformed traditional linear models. Gradient Boosting Regressor achieved an R² of 0.9671 for cycle time, while Extra Trees Regressor reached an R² of 0.9874 for warpage. Beyond prediction, the finalized surrogate models were used for Monte Carlo-based design space exploration with 1000 synthetic parameter combinations. Non-dominated solutions were identified to construct the Pareto front, and the top-ranked settings were compared with experimental results. The findings show that AutoML-based surrogate modelling can support both accurate prediction and process window identification in EPP foam injection molding. Full article

Controlling the interfacial behavior is essential for understanding the efficiency of surfactant–nanoparticle systems in practice. In this study, we investigate how silica (SiO₂) nanoparticles alter the surface and interfacial properties of sodium dodecyl sulfate (SDS) solutions at water–air and water–hexane interfaces, as well as their impact on the formation and stabilization of foams. While the negatively charged SiO₂ nanoparticles alone exhibit negligible surface activity, their combination with SDS leads to the formation of composite interfacial layers with enhanced surface pressure and dilational viscoelasticity. The increase in interfacial pressure reflects a high surface concentration and denser packing of SDS–SiO₂ associates. Interfacial rheology measurements show that SDS–SiO₂ nanofluids form more elastic interfacial films compared to pure SDS, with a maximum dilational elasticity at intermediate surfactant concentrations. This indicates the formation of mechanically stronger interfacial layers capable of resisting deformation. Foam experiments demonstrate that silica nanoparticles significantly improve foam formation and foam stability. These improvements correlate with increased surface pressure and interfacial elasticity, demonstrating that foam stability is primarily determined by the formation of robust interfacial layers and not solely by a reduction in surface tension. Overall, this study demonstrates how the presence of silica nanoparticles can affect the adsorption of SDS via hydrophobic interaction, leading to the formation of stronger interfacial films, improved foam stability, and expanded potential for applications in industrial processes, such as foam flooding based on nanoparticle/surfactant solutions to enhance oil–gas recovery. Full article

Carboxymethyl cellulose (CMC)-based materials are widely studied for functional materials and porous platform applications, yet their stability usually requires energy-intensive thermal curing or toxic chemical crosslinkers, which limit process sustainability. In this work, we present a more sustainable approach for the preparation of CMC-based foams using deep eutectic solvents (DES) as multifunctional structuring agents. CMC hydrogels were prepared with different DES at room temperature, followed by freeze-drying to obtain foams. Among the tested DES, choline chloride:oxalic acid (1:1) combined with glycerol produced foams with the most favorable properties, including high water uptake (288.24 ± 3.02% after 1 h) and water stability for 28 days. Morphological analysis revealed a homogeneous and interconnected porous network (32.2 ± 13.3 µm), while compression tests demonstrated good mechanical recovery (93.29 ± 3.12% over 10 cycles). Fourier transform infrared spectroscopy suggests interactions between CMC and DES, especially hydrogen bonds. The foams exhibited pH-dependent behavior, with limited resveratrol release under acidic conditions (22.2 ± 4.0% after 24 h), with significant release at pH 7.4 (85.30 ± 5.75%) and total release at pH 13.0. Drug release kinetics suggest a diffusion-controlled mechanism under acidic pH, transitioning to anomalous transport at higher pH values. This study demonstrates that DES can be used to prepare CMC-based foams, providing a more sustainable route to porous materials. Although biological validation is needed to confirm therapeutic safety, this study provides an initial physicochemical basis for using these matrices as tunable and stimuli-responsive porous materials. Full article

Low-frequency impact sound control remains a critical challenge for floating floor systems. Conventional resilient underlayment materials exhibit insufficient damping and are prone to long-term deformation, making stable low-frequency sound insulation difficult to achieve. This study presents the development of a composite floating floor underlayment comprising recycled rubber granules, polymer resin, and quartz sand. Based on the constrained layer damping-inspired (CLD-inspired) perspective, the vibration attenuation and noise reduction mechanism is elucidated, and the material’s physical properties, mechanical behavior, microstructure, and acoustic performance are systematically investigated. The results indicate that excessively large rubber granules aggravate curing shrinkage cracking. Optimal processing characteristics are achieved with a binder content of 20 wt% and a rubber granule size of 50 mesh. Laboratory characterization reveals that, compared with conventional cross-linked polyethylene (XLPE) foam underlayments, the proposed composite underlayment reduces the impact sound pressure level by an average of 3–5 dB in the low-frequency band below 250 Hz, and the overall sound insulation performance is improved by 10.77%. Dynamic mechanical analysis shows the composite storage modulus declines from 280 MPa at −20 °C to 10 MPa at 80 °C, while the loss factor remains above 0.2 under typical indoor conditions. Such stable viscoelastic behavior enables efficient shear dissipation of low-frequency vibration energy under the CLD-inspired mechanism. Full-scale field testing combined with long-term observation over 3000 loading cycles demonstrates excellent structural compatibility between the underlayment and the gypsum screed, with no cracking or appreciable deformation observed during prolonged service. The weighted impact sound improvement index (ΔLw) attains 15 dB. These findings verify that the CLD-inspired composite underlayment simultaneously achieves efficient low-frequency impact sound control and superior long-term structural stability, providing an innovative material solution and design strategy for impact noise mitigation in residential floating floor applications. Full article

Binder-free NiMn₂O₄@NiCo₂O₄ nanocomposites with NiMn₂O₄ nanoparticle (NP) surface coverage on NiCo₂O₄ nanosheets (NSs) are fabricated on nickel foam (NF) via a two-step microwave-assisted hydrothermal (MAH) method combined with annealing treatment, which can be used as a high-performance electrode material for supercapacitors. Specifically, a tulle-like NiCo₂O₄ nanosheet framework is first in situ grown on NF, followed by the growth of NiMn₂O₄ NPs on the surface of NiCo₂O₄ NSs via a secondary MAH process. To investigate the effect of the second-step holding time (HT) of MAH on material performance, a series of experiments were carried out with an HT of 15, 30, 45, and 60 min, and the microstructures and electrochemical properties of the products were analyzed. Structural characterization results confirm the successful synthesis of well-defined NiMn₂O₄-NPs@NiCo₂O₄-NSs composites. Electrochemical tests demonstrate that the product at an HT of 30 min has the best electrochemical performance with a higher specific capacitance of 441.56 F·cm⁻² at 1 A·cm⁻² and cycling stability (75% capacitance retention after 5000 cycles at 15 A·cm⁻²). The superior electrochemical properties are mainly attributed to the unique porous tulle-like NS structure with the largest specific surface area of the 30 min product. This distinctive structure affords abundant electrochemical active sites, effectively prevents structural collapse during long-term cycling, and shortens the transmission and diffusion pathways of electrons and electrolyte ions. The optimized NiMn₂O₄@NiCo₂O₄ electrode material presents extensive application prospects for high-performance supercapacitors. Full article

This study aimed to systematically compare the functional properties of the four major components (albumin, globulin, prolamin, and glutelin) of protein from Yunnan deep-veined walnuts to screen for protein-based carrier materials with good processing adaptability and the ability to efficiently encapsulate the active ingredient rutin. In addition, the binding and molecular interactions between the preferred protein and rutin were analyzed. The results indicated that albumin exhibited superior performance compared to the other three components in solubility, emulsifying properties, foaming properties, and gel properties, and demonstrated the strongest processing applicability. Further analysis revealed that albumin possessed an excellent amino acid composition (essential amino acid content accounting for 42.30%) and antioxidant activity (with the highest ABTS scavenging rate reaching 85.71 ± 0.26%), which indicated its considerable potential as a functional carrier. Loading rutin onto albumin yielded a walnut albumin–rutin complex (WA@Rut), which significantly enhanced the thermal stability of albumin (with the thermal denaturation temperature elevated to 108.72 °C) and the storage stability of rutin (66.16 ± 5.05% retention after 22 days of storage). Combined analyses of FT-IR spectroscopy, intrinsic fluorescence spectroscopy, molecular docking, and molecular dynamics simulations confirmed that rutin primarily bound to albumin via hydrogen bonding and electrostatic interactions, and formed a stable complex structure. SEM images revealed that the composite surface was smooth and exhibited a flake-like morphology. In conclusion, walnut albumin is a protein resource with significant functional potential in Yunnan deep-veined walnuts, and it exhibits strong processing applicability and enables efficient encapsulation and protection of active ingredients. This study provides novel strategies and theoretical foundations for the high-value utilization of walnut protein. Full article

In our research, we developed a Distributed Relaxation Spectrum Delay Differential Equation (DRSDDE) model to simulate viscoelastic responses exhibited by materials with multiple-scale relaxation mechanisms and finite delay times. Our model expanded upon traditional integer-order viscoelastic models to include a continuum relaxation process using a log-time-space Gaussian distribution representing a continuum of relaxation processes, including a direct representation of the effect of delayed feedback via an explicit time delay term. Consequently, the resultant model can be viewed as a generalized Maxwell-type formulation where the viscoelastic behavior exhibits distributed relaxation dynamics and has finite signal propagation characteristics. We then used experimental data obtained from three representative materials: PDMS Sylgard 184, bovine brain white matter, and polyurethane foam to calibrate the model. Calibration was achieved by estimating model parameters through the use of Gauss-Legendre quadrature combined with non-linear optimization of the relaxation spectrum. The results indicate that the coefficients of determination for each of the materials exceeded $R^2>0.83$. Therefore, the proposed DRSDDE model outperformed the classical Zener model when simulating materials that exhibit a wide relaxation spectrum. The parameter values estimated for each of the examined materials provided additional insight into their physical behaviors. Specifically, the characteristic relaxation times for the studied materials were determined based upon ${\tau }_c= {10}^{\mu }$ ranging from about 63 s to 158 s. These results illustrate different dominant relaxation regimes for the investigated materials. Additionally, both characteristic equations and frequency domain analyses were utilized to study the stability and bifurcation properties of the DRSDDE model. A significant finding resulted from identifying a delay-insensitive stability regime for materials with $\tilde{K}< 1$ (as illustrated by bovine brain white matter). For materials with $\tilde{K} > 1$, the analysis revealed Hopf bifurcation results illustrating critical delay thresholds and frequencies for the onset of oscillations. Further, it was established that all calibrated delay values were significantly less than these threshold values. This indicates that all identified models functioned well below the oscillation thresholds at realistic delay times. Ultimately, the proposed DRSDDE model represents a physically intuitive, robust, and flexible method for modeling complex viscoelastic systems. Future research will involve investigating temperature-dependent effects, nonlinear bifurcations, and experimental validations of predicted oscillatory dynamics. Full article

Carbon/inorganic hybrid composites have evolved from filler-reinforced materials into design platforms for coupled electromagnetic, thermal, sensing, environmental, protective and energy-related functions. Their distinctive value lies in the possibility of combining a conductive, polarizable or porous carbon phase with an inorganic phase that contributes dielectric, magnetic, catalytic, ionic, thermally conductive or barrier behavior. This review examines carbon/inorganic hybrid multifunctional composites from the viewpoint of structure–property relationships, with emphasis on interfacial design, percolation, anisotropy, hierarchical architecture, processing and metrology. Selected graphitic composite studies are discussed as case studies for broadband dielectric spectroscopy, microwave shielding, high-frequency contact metrology, thermal diffusivity analysis and impedance-monitored graphene filters; these case studies are integrated with the broader international literature on CNT and graphene polymer composites, MXene films and foams, graphene/metal oxide photocatalysts, boron nitride/carbon thermal networks, biochar–graphene adsorbents, smart coatings, sensors, supercapacitors and water remediation systems. The central argument is that credible multifunctionality requires more than measuring several properties on the same material. It requires simultaneous or service-relevant co-optimization under constraints of thickness, density, processability, aging, humidity, corrosive media, regeneration, toxicity, economic feasibility and scalable fabrication. The review concludes with design rules and reporting recommendations intended to help move the field from impressive property demonstrations toward application-ready hybrid material systems. Full article